No, this isn’t from The Onion. Trained wasps:
The tiny, non-stinging wasps can check for hidden explosives at airports and monitor for toxins in subway tunnels.
“You can rear them by the thousands, and you can train them within a matter of minutes,” says Joe Lewis, a U.S. Agriculture Department entomologist. “This is just the very tip of the iceberg of a very new resource.”
Sounds like it will be cheap enough….
EDITED TO ADD (12/29): Bomb-sniffing bees are old news.